Pipe coupling with flexible sealing lip



- June 29, 19 I s. GUARNASCHELLI I 1 3 PIPE COUPLING WITH FLEXIBLESEALING LIP Filed Feb. 1, 1963 Fluid Flow INVENTUR.

W mmm w AT TOR NEYJ United States Patent 1 Claim. (Cl. 285-110) Thisinvention relates to means for connecting tubular elements together andmore particularly to the sealing of confronting faces at a fitting. Theinvention is intended more particularly for the sealing of conical seatfittings.

It is an object of the invention to provide an improved tubingconnection and more especially a tube fitting in which the leakage offluid from the fitting is prevented, at least in part, by sealingpressure exerted by the fluid flowing through the fitting.

One feature of the invention relates to a construction of a fitting insuch a way that one of the confronting faces of the fitting is yieldableand has space behind it into which fluid enters to exert a pressuretoward the other face. There is a connection between the elements of thefitting against which the reaction force is exerted.

Other objects, features and advantages of the invention Will appear orbe pointed out as the description proceeds.

In the drawings, forming a part hereof, in which like charactersindicate corresponding parts in all the views;

FIGURE 1 is a side view, partly in section, showing a fitting made inaccordance with this invention; and

FIGURES 2 and 3 are sectional views taken on the lines 2-2 and 33respectively, of FIGURE 1.

The fitting illustrated in FIGURE 1 includes a first element 11 having aconical seat 12 at one end. A short distance back from the conical seat12 there are threads 14 extending along a portion of the outside surfaceof the fitting element 11. The other end of the element 11 has threads15 for connecting it with a coupling or any other part of a pipe systemin which the fitting is to be used. There is a polygonal flangeintermediate the ends of the fitting element 11 for receiving a wrench.

A second fitting element 21 has a face 22 which is complementary to theface 12. In the preferred construction, these faces are frusto-conicaland have the same angle of taper as conventional commercial fittings,that is, 37 /2" or 45.

The face 22 is on the outer surface of a flange 25 which is an inwardlyturned lip of the fitting element 21 in the construction illustrated.This flange 25 is resilient and has suflicient flexibility so that itcan be distorted slightly by pressure behind it to obtain a tight sealbetween the faces 12 and 22. There is an annular pocket 27 behind theflange 22 and this pocket 27 opens into the passage through the fitting21 so that the pressure of the fluid in this fitting element 21 isexerted against the back of the flange 25.

The diameter of the passage through the flange 25 is smaller than thediameter of the fitting element 21. The diameter of the passage in thefirst fitting element 11 is also smaller than the diameter of thepassage through the second fitting element 21 behind the flange 25. Thepurpose of these reductions in diameter is to obtain a pressuredifference for sealing the flange 25 against the seat 12 when thedirection of fluid is that indicated by the arrow 30.

In any piping system there is a progressive reduction in ice pressurefrom the upstream to the downstream end of the system. With thisinvention, a reduction in diameter and cross section of the passage isused to produce a greater pressure drop at the region where the pressureis to be used for sealing the fitting. For example, the pressureupstream from the flange 25 is indicated by legend P-l. The pressuredownstream from the flange 25 is indicated by legend P-2. Because of thepartial obstruction offered by the reduction in cross section of thepassage, P-l substantially greater than P-2 and it can be made larger orsmaller, in proportion to P-2 by designing the fitting with variouschanges in diameter.

In the preferred construction, the flange 25 extends inwardly beyond theinside wall of the fitting 11 and this inside Wall has a smallerdiameter than the passage through the fitting 21 upstream from theflange 25.

While this relation is advantageous because of the combined static anddynamic pressure exerted against the flange 25, the construction can bemodified by having the passage through the flange equal or less than thereduced passage diameter in the fitting 11 downstream from the flange;or the passage in the fitting 11 can be made with the same diameter asthe passage through the fitting 21 upstream from the pocket 27.

The fitting elements 11 and 21 are held together by a nut 33. This nut33 fits over the threads 14 of the fitting element 11 and there is a lip35 at one end of the nut 33. This lip 35 fits behind a shoulder 36 onthe outside of the fitting 21 for clamping the fitting 21 against thefitting 11. When the nut is tightened, the flange 25 yields to conformtightly to face 12 and maintains a spring loading which prevents leakageor loosening of the connection. Flange 25 is formed so that the best fitis made when the nut is tightened.

When fluid pressure in the pocket 27 is exerted against the back of theflange 25, there is a reaction pressure, in the opposite directionagainst the other side of the pocket. Because of this reaction pressure,and the longitudinal pressure in the piping system, the pressure of thefluid against the back of the flange 25 cannot be used to hold thefitting elements ll and 21 together. The nut 33 is used, therefore, toprovide a connection between the fittings against which the reactionforce can be exerted so that the fluid pressure behind the flange 25 iseffective for thrusting the face 22 of the flange tightly against theface 12 of the first fitting element 11.

The fitting element 21 is shown without threads and it is intended to besecured to a tube end, or other part of the piping system, by sweating,brazing, welding, or any other suitable method of bonding. The inventioncan, however, be made with threads on the fitting 21 if such aconstruction is desired.

The preferred embodiment of the invention has been illustrated anddescribed, but changes and modifications can be made, and some featurescan be used in different combinations without departing from theinvention as defined in'the claim.

What is claimed is:

A tube joint for fluid pressure sealing when fluid flows in onedirection through the joint comprising,

a first fitting element having an inwardly extending conical face, asecond fitting element having an inwardly extending reentrantly bentyieldable resilient conical flange, said flange having a complementaryface contacting that of said first fitting element, an

annular pocket formed at the apex of said reentrant bend and opening onthe upstream side of said flange, the upstream surface of said flangebeing exposed via said annular pocket to the fluid pressure caused byfluid flow on the upstream side thereof, whereby said flange isyieldably responsive to fluid flow pressure, said second fitting havinga larger inside cross section exposed to the fluid flow on the upstreamside of the flange than on the downstream side, the conical face of saidfirst fitting sloping inwardly toward the adjacent end of said firstfitting element, n55 confronting face on said second fitting elementbeing sloped at an angle of taper so as to bear on said first fittingelement, and fastening means for holding said fitting elements together.

References Cited by the Examiner UNITED STATES PATENTS 1,589,469 6/26Homand 285-100 1,656,222 1/28 Oakley 285386 2,558,695 6/51 Unger 285-410X 3,069,187 12/62 Collins et al. 285-110 3,145,035 8/64 Hanback.

FOREIGN PATENTS 272 93 Great Britain.

CARL W. TOMLIN, Primary Examiner.

